Polyurethanes

ABSTRACT

Novel polyurethanes are prepared in the novel process which comprises reacting a polyisocyanate, such as toluene diisocyanate, with an oxaminated polyol. The oxaminated polyols described herein are polyols which have been reacted with a mixture of an N-substituted aziridine and a monoepoxide; such as polyoxypropylene glycol which has been reacted with a mixture of N-ethyl aziridine and ethylene oxide.

United States Patent Parrish et al.

[ 51 July 11, 1972 POLYURETHANES Donald Bob Parrish; Ronnie Mac Pruitt,both of Lake Jackson, Tex.

The Dow Chemical Company, Midland, Mich.

Filed: March 27, I970 Appl. No.2 23,508

Inventors:

Assignee:

us. a. ..260/2.5 AQ, 260/77.5 AM, 260/775 AQ Int. Cl. ..C08g 22/14, C08822/44 Field of Search ..260/2.5 A0, 77.5 A0, 75 T,

Relerences Cited UNITED STATES PATENTS 6/1966 Kuryla ..260/77.5 AQ3/1967 Thiers ..260/77.5 AQ

3,134,755 5/I964 Miiller ..260/2.5 AQ

OTHER PUBLICATIONS Product Report Isonol C I00; Upjohn Chemical Co.,Sept. l, 1966, 1 page.

Primary Examiner-Donald E. Czaja Assistant Examiner-C. Warren IvyA!Iorne v -Griswold & Burdick and C. E. Rehberg [57] ABSTRACT 13 Claims,No Drawings SUMMARY OF THE INVENTION It has now been discovered thatnovel polyurethanes are produced in the novel reaction comprisingreacting by contacting a polyisocyanate with an oxaminated polyol. Byoxaminated polyol is meant the reaction product of (I) an N- substitutedaziridine, (2) a monoepoxide, and (3) a polyol, i.e. an aliphaticcompound bearing at least two alcoholic hydroxyl groups. The oxaminatedpolyol may be used in the reaction mixture as the sole source ofhydroxyl hydrogen, or it may be included in admixture with aconventional polyol or other oxaminated polyols.

The major advantage of the invention is that the novel process requireslittle, if any, additional catalyst since the tertiary amino groupscontained in the backbone structure act as the catalyst. Further, thenovel polyurethanes thus produced have excellent physical properties.

The oxaminated polyols suitable for use in this invention may berepresented by the structural formula:

wherein A O -l-,, is the g-valent residue derived by removal of q atomsof active hydrogen from a polyol; q is an integer of from I to about 8;m is an integer of from to about lSO or more; n is an integer of from Ito about 60. R, is hydrogen or alkyl, such as methyl, ethyl, propyl,octyl, decyl, dodecyl, octadecyl, and the like; aryl, such as phenyl,naphthyl, and the like; aralkyl, such as benzyl, phenethyl,4-phenylbutyl, 3,5- dimethylphenethyl, 4-t-butylbenzyl,4-decylphenethyl, and the like; alkaryl, such as tolyl, xylyl,4-butylphenyl, and the like; alkenyl, such as vinyl, allyl, and thelike; alkoxyalkyl, such as methoxymethyl, butoxymethyl, and the like;al- .kenyloxyalkyl, such as allyloxymethyl, butenyloxyethyl, and thelike, and is preferably hydrogen, methyl, ethyl, or allyloxymethyl, andis most preferably hydrogen or methyl. R is hydrogen or lower alkyl offrom one to six carbon atoms, such as methyl, ethyl, butyl and hexyl,and is preferably hydrogen or methyl, and most preferably is hydrogen. Ris alkyl, such as ethyl, propyl, butyl, octyl, dodecyl and the like;aryl, such as phenyl, and the like; aralkyl, such as benzyl, phenethyl,3- phenylpropyl, 2,4-dimethylphenethyl, 4-octylbenzyl, 4-dodecylphenethyl, and the like; alkenyl, such as allyl, butenyl, and thelike; cycloaliphatic, such as cyclohexyl, cyclopentadienyl, and thelike; alkoxycarbonylalkyl such as ethoxycarbonylethyl (carbethoxyethyl),methoxycarbonylethyl-(carbomethoxyethyl), 2-butoxycarbonylpropyl, andthe like; alkanoyloxyalkyl, such as acetyloxyethyl,2-pr0pionyloxypropyl, hexanoyloxyethyl, and the like; alkenoyloxyalkyl,such as acryloyloxymethyl (CI-I CH-COOCH,), methacryloyloxyethyl,2-methacryloyloxypropyl, and the like, and such groups bearingsubstituents such as halo, cyano, etc., e.g. 2-chloroethyl, cyanoethyl,etc., and preferably is alkyl or aralkyl of from two to 12 carbon atoms,and is most preferably ethyl, Z-cyanoethyl or phenethyl. Examples ofsuitable such oxaminated polyols include the reaction product of: (a)water (0.25 to about l5 percent by weight, based on the totalcomposition weight), N-ethylaziridine and ethylene oxide and/orpropylene oxide; (b) ethylene glycol or glycerol, N- ethylaziridine andethylene oxide and/or propylene oxide; (c) sorbitol,N-phenethylaziridine and ethylene oxide; (d) mannitol,N-cyanoethylaziridine and propylene oxide or butylene oxide; (e)glycerol, N-2-hydroxyethyI-aziridine and ethylene oxide, (f)polyethylene glycol or polypropylene glycol, N- ethylaziridine andethylene oxide and/or propylene oxide; (g) sucrose, Nphenethylaziridineand allyl glycidyl ether; and other like compounds. In (a) water firstreacts with the epoxide to form a glycol which is then oxaminated.

The oxaminated polyols are prepared by reacting, in substantially liquidphase, the polyol with an N-substituted aziridine having the formulawherein R and R have the above meaning, and an epoxide having theformula wherein R, has the above meaning. Suitably, the reactiontemperatures range from about '25 C. up to about 250 C. and preferablyfrom about 75 C. up to about C. The pressure is preferably autogenous.The mole ratio of N-substituted aziridine to epoxide may besubstantially any value and the net result will be an alternatingcopolymer of the monomers but the ratio is preferably from about 1:10 to10:1 and is most preferably from about 1:2 to 2:I. The reaction timevaries from a few hours to a few days depending upon the reactiontemperature. If desired, the oxaminated polyols may be subsequentlyreacted with any of the alkylene oxides to further increase themolecular weight of the oxaminated polyol or to provide a particular"end-cap for the molecule.

The reactivity of the oxaminated polyols with the polyisocyanateincreases with increasing amounts of nitrogen in their backbone. Hence,for low reactivity, one would use a high molecular weight polyol toprepare the oxaminated polyol, and vice versa. A mixture of theoxaminated polyol with other polyols likewise can be used to controlreactivity.

Suitable polyisocyanates in this invention may be any from the knownclass of polyisocyanates bearing two or more isocyanate groups and whichare conventionally used in preparing polyurethanes. Examples of suitablesuch polyisocyanates include hexamethylene diisocyanate, 2,4- and/or2,6-tolylene diisocyanate (TDI), xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate, (MDI), mand/or p-phenylene diisocyanate, naphthylenediisocyanate, and polymers bearing a plurality of isocyanate groups,such as polymethylene polyphenylisocyanate and the like. MDI, TDI andpolymethylene polyphenyl isocyanate are the preferred polyisocyanates.In preparing the polyurethanes, the polyisocyanate and polyol componentsare mixed in a ratio such that there is about 0.9 isocyanate equivalentper hydroxy equivalent and preferably from 1 to about 1.15 isocyanateequivalents per hydroxy equivalent.

Other ingredients may be included in the polyurethane compositions, suchas conventional metal salt catalysts, such as stannous oleate, stannousoctoate, dibutyltin dilaurate, and the like, as illustrated in US. Pat.No. 3,391,091, fire-retardant agents, such as a phosphorus-containingpolyol, blowing agents, fillers, cellcontrol agents and the like.

Suitable blowing agents include the low-boiling hydrocarbons andhalohydrocarbons, such as methylene chloride, trichlorofluoromethane,and the like. In flexible polyurethane foams, water may also be employedas a blowing agent.

Suitable cell-control agents include silicone oils, and other knowncompounds.

The subject polyurethanes can be formulated and processed in aconventional manner to produce both rigid and flexible polyurethanefoams, including those known as semi-rigid and semi-flexible as well asthe non-foamed polyurethane elastomers.

SPECIFIC EMBODIMENTS The following examples further illustrate theinvention.

EXAMPLE 1 N-Ethylaziridine (315 g.), propylene oxide (234 g.) andpolypropylene glycol (2,000 g.; prepared by condensing propylene oxide(PO) onto a glycerol in the presence of KOH; average molecular weight of3,000) were charged into an autoclave. The autoclave was sealed andheated to l75-l 85 C. and maintained at that temperature for hours. Thevolatiles were removed from the reaction mixture under reduced pressureleaving 2,456 g. of product. The product had a viscosity of 497centistokes at C., a Gardner color of l and a 1.58 percent hydroxylcontent, percent by weight based on the total product weight.

Several polyurethane foams were prepared using the ox- Polypropyleneglycol molecular weight of 3,000, as described above.

"Oxaminated polyol the above reaction product.

"TDl 80/20 an 80/20 mixture by weight of 2,4-tolylene diisocyanate and2,6tolylene diisocyanate, respectively. Niax A-l a commerciallyavailable bis(dimethylamino) ethyl ether.

product which is In the examples, all of the components, except thepolyisocyanate component, were first blended together, thepolyisocyanate was then blended into the mixture and the resultantformulation allowed to stand at room temperature until the reactionceased.

The physical properties of the resulting foams were determined and aresummarized below.

TABLE 2 Run No.

Density, lbs/ft 1.49 155 L53 Modulus l.6l l.8l 1.63 Tensile, psi. 14.4l6.l l3 Elongation, 7( 178 230 I76 Tear Resistance, lbs/in. 2.4 2.1 2.3Compression Set., 90% 6.9 7.9 6.5 7r Hystersis Return 69 75 67 RiseTime, sec. 70 70 72 Sag factor which is 65% Indentation LoadDeflection/25% Indentation Load Deflection Rigid polyurethanes areprepared by using oxaminated polyols described herein derived frompolyols having a high degree of functionality and/or a low molecularweight, such as sorbitol, sucrose.

Flexible polyurethanes are prepared by using oxaminated polyolsdescribed herein derived from polyols having a low degree offunctionality and/or a high molecular weight, such as polypropyleneglycol or glycerol initiated polypropylene glycol.

Curable polyurethanes are prepared by using oxuminutcd polyols describedherein bearing polymerizuble vinyl groups, i.e. R, and/or R, are alkenylgroups, such as vinyl, allyl, p-vinyl benzyl. etc., within thedefinition of R, and R above. Such polyurethanes may be vulcanized withsulfur or other known cross-linking agents for vinyl compounds.Additionally, cura ble polyurethanes are prepared by using an excess ofthe polyisocyanate component in the reaction so that the resultingpolyurethane bears available isocyanate groups for cross-linking; suchpolymers may be cured with water, glycols, and other active hydrogencontaining compounds.

We claim:

1. A polyurethane composition comprising, in a chemically combined form,(a) a polyisocyanate and (b) an oxaminated polyol having the structuralformula A- 0 CIh IlI-O 01M411! Nt/IIzUIIU- JI:I L L M t 1..

wherein A l- O 4-,, is a q-valent residue derived by removal of q atomsof active hydrogen from an aliphatic polyol; q is an integer offrom 1 to8; m is an integer offrom 0 to n is an integer of from 1 to 60; R, ishydrogen, alkyl, aryl, alkaryl, alkenyl, alkoxyalkyl or alkenyloxyalkyl;R is hydrogen or lower alkyl of from one to six carbon atoms; R, isalkyl of from l-4 carbon atoms, aralkyl, alkenyl, cycloaliphatic,alkoxycarbonylalkyl, alkanoyloxyalkyl, alkenyloxyalkyl, or such groupsbearing haloor cyano-substituents.

2. The composition defined in claim 1 wherein (a) is at least one ofhexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylenediisocyanate, xylylene diisocyanate, diphenylmethane-4,4'-diisocyanate,mor p-phenylene diisocyanate, naphthylene diisocyanate or polymethylenepolyphenylisocyanate.

3. The composition defined in claim 2 wherein (a) is at least one of2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,diphenylmethane-4,4-diisocyanate, or polymethylene polyphenylisocyanate.

4. The composition defined in claim 1 wherein R, is hydrogen, methyl,ethyl or allyloxy.

5. The composition defined in claim 1 wherein R is hydrogen or methyl.

6. The composition defined in claim 1 wherein R is alkyl of from two tofour carbon atoms or aralkyl of from two to 12 carbon atoms.

7. The composition defined in claim 1 wherein R;, is ethyl, 2-cyanoethyl or phenethyl.

8. The composition defined in claim 1 as a foam.

9. The composition defined in claim 4 wherein R is hydrogen or methyl.

10. The composition defined in claim 9 wherein R is alkyl or aralkyl offrom two to l2 carbon atoms.

11. The composition defined in claim 3 wherein R, is hydrogen, methyl,ethyl or allyloxy; R is hydrogen; and R is ethyl, 2-cyanoethyl orphenethyl.

12. The composition defined in claim 1 wherein said aliphatic polyol isethylene glycol, glycerol, sorbitol, mannitol, sucrose, polyethyleneglycol, or polypropylene glycol.

13. The composition defined by claim 11 wherein said aliphatic polyol isethylene glycol, glycerol, sorbitol, mannitol, sucrose, polyethyleneglycol, or polypropylene glycol.

2. The composition defined in claim 1 wherein (a) is at least one ofhexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2, 6-tolylenediisocyanate, xylylene diisocyanate, diphenylmethane-4,4''-diisocyanate,m- or p-phenylene diisocyanate, naphthylene diisocyanate orpolymethylene polyphenylisocyanate.
 3. The composition defined in claim2 wherein (a) is at least one of 2,4-tolylene diisocyanate, 2,6-tolylenediisocyanate, diphenylmethane-4,4''-diisocyanate, or polymethylenepolyphenylisocyanate.
 4. The composition defined in claim 1 wherein R1is hydrogen, methyl, ethyl or allyloxy.
 5. The composition defined inclaim 1 wherein R2 is hydrogen or methyl.
 6. The composition defined inclaim 1 wherein R3 is alkyl of from two to four carbon atoms or aralkylof from two to 12 carbon atoms.
 7. The composition defined in claim 1wherein R3 is ethyl, 2-cyanoethyl or phenethyl.
 8. The compositiondefined in claim 1 as a foam.
 9. The composition defined in claim 4wherein R2 is hydrogen or methyl.
 10. The composition defined in claim 9wherein R3 is alkyl or aralkyl of from two to 12 carbon atoms.
 11. Thecomposition defined in claim 3 wherein R1 is hydrogen, methyl, ethyl orallyloxy; R2 is hydrogen; and R3 is ethyl, 2-cyanoethyl or phenethyl.12. The composition defined in claim 1 wherein said aliphatic polyol isethylene glycol, glycerol, sorbitol, mannitol, sucrose, polyethyleneglycol, or polypropylene glycol.
 13. The composition defined by claim 11wherein said aliphatic polyol is ethylene glycol, glycerol, sorbitol,mannitol, sucrose, polyethylene glycol, or polypropylene glycol.